Applied Mathematics and Mechanics (English Edition) ›› 2019, Vol. 40 ›› Issue (1): 85-96.doi: https://doi.org/10.1007/s10483-019-2402-9

• 论文 • 上一篇    下一篇

Free vibration of non-uniform axially functionally graded beams using the asymptotic development method

Dongxing CAO1,2, Yanhui GAO1,2   

  1. 1. College of Mechanical Engineering, Beijing University of Technology, Beijing 100124, China;
    2. Beijing Key Laboratory of Nonlinear Vibrations and Strength of Mechanical Structures, Beijing 100124, China
  • 收稿日期:2018-03-09 修回日期:2018-06-18 出版日期:2019-01-01 发布日期:2019-01-01
  • 通讯作者: Dongxing CAO E-mail:caostar@bjut.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (No. 11672008)

Free vibration of non-uniform axially functionally graded beams using the asymptotic development method

Dongxing CAO1,2, Yanhui GAO1,2   

  1. 1. College of Mechanical Engineering, Beijing University of Technology, Beijing 100124, China;
    2. Beijing Key Laboratory of Nonlinear Vibrations and Strength of Mechanical Structures, Beijing 100124, China
  • Received:2018-03-09 Revised:2018-06-18 Online:2019-01-01 Published:2019-01-01
  • Contact: Dongxing CAO E-mail:caostar@bjut.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (No. 11672008)

摘要: The asymptotic development method is applied to analyze the free vibration of non-uniform axially functionally graded (AFG) beams, of which the governing equations are differential equations with variable coefficients. By decomposing the variable flexural stiffness and mass per unit length into reference invariant and variant parts, the perturbation theory is introduced to obtain an approximate analytical formula of the natural frequencies of the non-uniform AFG beams with different boundary conditions. Furthermore, assuming polynomial distributions of Young's modulus and the mass density, the numerical results of the AFG beams with various taper ratios are obtained and compared with the published literature results. The discussion results illustrate that the proposed method yields an effective estimate of the first three order natural frequencies for the AFG tapered beams. However, the errors increase with the increase in the mode orders especially for the cases with variable heights. In brief, the asymptotic development method is verified to be simple and efficient to analytically study the free vibration of non-uniform AFG beams, and it could be used to analyze any tapered beams with an arbitrary varying cross width.

关键词: analytical mechanics, nonholonomic constraint, variable mass, noninertial reference frame, first integral, integral invanant, natural frequency, axially functionally graded(AFG)beam, non-uniform, asymptotic development method

Abstract: The asymptotic development method is applied to analyze the free vibration of non-uniform axially functionally graded (AFG) beams, of which the governing equations are differential equations with variable coefficients. By decomposing the variable flexural stiffness and mass per unit length into reference invariant and variant parts, the perturbation theory is introduced to obtain an approximate analytical formula of the natural frequencies of the non-uniform AFG beams with different boundary conditions. Furthermore, assuming polynomial distributions of Young's modulus and the mass density, the numerical results of the AFG beams with various taper ratios are obtained and compared with the published literature results. The discussion results illustrate that the proposed method yields an effective estimate of the first three order natural frequencies for the AFG tapered beams. However, the errors increase with the increase in the mode orders especially for the cases with variable heights. In brief, the asymptotic development method is verified to be simple and efficient to analytically study the free vibration of non-uniform AFG beams, and it could be used to analyze any tapered beams with an arbitrary varying cross width.

Key words: analytical mechanics, nonholonomic constraint, variable mass, noninertial reference frame, first integral, integral invanant, non-uniform, axially functionally graded(AFG)beam, natural frequency, asymptotic development method

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